1. Field of the Invention
The present invention is directed to a distributed data acquisition, processing and analysis system which allows continuous diagnostic monitoring of sensors and alerts operators, via a remote processor, whenever a component being monitored by the sensors is abnormal, indicating an actual or potential failure without burdening the remote processor with detailed diagnostic signal processing and analysis.
2. Description of the Related Art
Component monitoring systems have traditionally been centralized systems in which a computer is directly connected to the remotely located sensors monitoring major plant components throughout a processing plant, such as a nuclear power plant. In these systems, the remote processor monitors the state of the sensors to determine the state of the components. In these traditional systems, the computer spends a relatively large amount of time processing and analyzing the sensor signals which limits the number of sensors/components that can be monitored. There are predominantly two methods currently used to implement plant component diagnostic monitoring. The first method involves the processing of all sensor data within the plant at a central location. The central monitor will process and analyze one sensor signal at a time and alert an operator when servicing is required. While such an installation has the advantage of having all of the extensive sensor processing and analysis equipment located at a convenient location, several disadvantages exist. Recent diagnostic algorithms depend on the conversion of sensor signals into a sequence of digital numbers to be analyzed using computationally intensive digital signal processing algorithms, such as spectral analyses. Even with the use of state-of-the-art digital computer systems, a limited number of sensors may be monitored at times when extensive digital signal processing algorithms are needed. Another disadvantage of implementing multisensor diagnostic monitoring with equipment located only at a central location is the cost of cabling for each sensor and the cost of implementing a multisensor data communication scheme with a drop for each sensor. Any cabling issue is of extreme importance for systems installed in an existing or new power plant. In addition, because wiring runs for sensors throughout a plant are of different lengths, signal conditioning circuitry with different signal conditioning parameters is necessary for each different sensor type, further exacerbating the maintenance problem.
A second method uses portable monitors, such as a computer or analog recording device, carried by service personnel throughout the plant to record data from component sensors. This method invests a significant amount of resources in service personnel, rather than capital equipment.
Diagnostic monitoring techniques for major plant components using a variety of sensors have proven valuable in achieving high availability and lowering maintenance costs of plant components such as pumps, valves and motors. Diagnostic monitoring typically involves recording certain processed quantities of the sensors when the component is known to be functioning properly and watching for changes in the quantities. These changes are observed well in advance of a failure and many times the exact problem may be diagnosed. A service organization using diagnostic monitoring will, therefore, have the opportunity to order the required parts and schedule maintenance before a failure occurs.